Coving (also known as cornice and crown moulding) and skirting board (also known as baseboard) are lengths of material formed and positioned to extend along a wall either between the wall and ceiling (coving), or the bottom of a wall and the floor (skirting board). The purpose is for the coving or skirting board to act as a decorative material to conceal or dress the corner joint between the wall/ceiling or wall/floor. Where two walls meet, the ends of the coving or skirting board are cut at an angle (a mitre cut) to mutually abut—for example, if two vertical walls meet at 90 degrees, then the ends of the coving/skirting board running along each wall will be mitre cut at 45 degrees to form two substantially identical end faces at an angle of 45 degrees to the main face of the skirting board, the end faces extending from or into the corner to abut one another. These angled or mitre cuts are generally considered to provide a more aesthetically pleasing finish than having an end face of one length of skirting board abut the side of the neighbouring length at its end. If a 45 degree cut is required, there are a number of tools that can be used, such as for example the Coving Cornice Mitre Template tool shown in FIG. 1. This is a non-adjustable tool formed as a unitary item by plastic injection moulding, or stamping and forming from a metal sheet. The two sides are substantially perpendicular to one another so that when the outer ends are positioned on a length of coving, the faces of each side will be aligned at an angle of 45 degrees to the main longitudinal axis of the coving.
One problem that is frequently encountered when fitting coving or skirting board is that wall corners are often not precisely 90 degree right angles. This is frequently the case with older buildings, or in buildings where the walls were squared by hand. In addition, many buildings contain features where two adjacent walls are intentionally formed so as not to meet at right-angles—for example if a room has a feature such as a bay window.
There are a number of methods and tools currently in use for measuring the corner angle so as to correctly mitre cut coving or skirting board, so that the ends of adjacent lengths will meet cleanly.
One common method involves using a sliding bevel gauge and a set of complex calculations, the results of which are transferred to a compound mitre saw to cut the coving or skirting board. Alternatively, a tool such as the Bosch GAM angle finder (or a similar angle finder) can be used to measure the corner and again transfer the required cut measurements to a separate tool for cutting. Both of these methods are complex, lengthy, and (if using a power saw) noisy and messy, especially for coving mitres.
U.S. Pat. No. 4,608,899 describes and shows a tool for guiding mitre cuts, where the angle between the two faces can be adjusted. However, the tool described can only be used for internal corners due to the placement of the hinge and locking mechanism, which prevents the tool from pressing flush against an external corner. Furthermore, when the angle of the cut is not for a 90 degree corner, the angle of the mitre and angle of the bevel change so that two separate measurements need to be calculated and marked in order to make the cut. The tool does not calculate the angles required, nor does it display the angle that it is adjusted to.
For measuring and cutting skirting board mitres where different angles may be required, the current practice is to use a sliding bevel gauge and then bisect triangles on the rear face of the skirting board in order to determine the angle of the mitre, or alternatively to use a digital protractor, calculate the required cut and transfer the measurement to a compound mitre saw.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.